Light Emitting Display Device

Abstract

In a light emitting display device according to an embodiment of the present disclosure, lateral leakage current caused by a layer having high mobility in the device is prevented by changing an internal structure of a stack of light emitting elements. The light emitting display device of the disclosure includes a bank to expose a plurality of light emitting portions spaced apart from each other on a substrate, a first electrode at each of the plurality of light emitting portions and a second electrode to face the first electrode, a first stack, a second stack and a charge generation layer between the first electrode and the second electrode, and an optical compensation layer located between the charge generation layer and the first stack and in contact with the charge generation layer at at least one of the plurality of light emitting portions.

What is claimed is: 
     
         1 . A light emitting display device comprising:
 a bank to expose a plurality of light emitting portions spaced apart from each other on a substrate;   a first electrode at each of the plurality of light emitting portions and a second electrode to face the first electrode, the second electrode over the plurality of light emitting portions;   a first stack, a second stack, and a charge generation layer between the first electrode and the second electrode; and   an optical compensation layer located between the charge generation layer and the first stack at at least one of the plurality of light emitting portions and in contact with the charge generation layer.   
     
     
         2 . The light emitting display device according to  claim 1 , wherein the optical compensation layer has an edge on a bank adjacent to the at least one of the plurality of light emitting portions. 
     
     
         3 . The light emitting display device according to  claim 1 , wherein the optical compensation layer is thicker than the charge generation layer. 
     
     
         4 . The light emitting display device according to  claim 1 , wherein the optical compensation layer comprises an electron transport material. 
     
     
         5 . The light emitting display device according to  claim 1 , wherein:
 the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer; and   the N-type charge generation layer is in contact with the optical compensation layer.   
     
     
         6 . The light emitting display device according to  claim 1 , wherein a thickness of the charge generation layer is smaller on the optical compensation layer above the bank than on the optical compensation layer at the at least one of the plurality of light emitting portions. 
     
     
         7 . The light emitting display device according to  claim 2 , wherein:
 an optical compensation layer non-formation area is provided on the bank adjacent to the edge of the optical compensation layer; and   the charge generation layer is in contact with an electron transport layer of the first stack at the optical compensation layer non-formation area.   
     
     
         8 . The light emitting display device according to  claim 1 , wherein:
 the plurality of light emitting portions includes a first light emitting portion, a second light emitting portion, and a third light emitting portion;   the first light emitting portion includes a first blue light emitting layer and a second blue light emitting layer in the first stack and the second stack, respectively;   the second light emitting portion includes a first green light emitting layer and a second green light emitting layer in the first stack and the second stack, respectively;   the third light emitting portion includes a first red light emitting layer and a second red light emitting layer in the first stack and the second stack, respectively; and   the optical compensation layer includes a first optical compensation layer in the second light emitting portion and a second optical compensation layer in the third light emitting portion.   
     
     
         9 . The light emitting display device according to  claim 8 , wherein:
 the first light emitting portion does not have an optical compensation layer, and   the charge generation layer on the bank, comes into contact with an electron transport layer of the first stack at a region adjacent to the first light emitting portion and comes into contact with the first optical compensation layer or the second optical compensation layer as a distance from the first light emitting portion increases.   
     
     
         10 . The light emitting display device according to  claim 8 , wherein the second optical compensation layer is thicker than the first optical compensation layer. 
     
     
         11 . The light emitting display device according to  claim 1 , further comprising an additional stack and an additional charge generation layer between the second stack and the second electrode. 
     
     
         12 . The light emitting display device according to  claim 11 , wherein the additional charge generation layer is in contact with an additional optical compensation layer overlapping the optical compensation layer. 
     
     
         13 . A light emitting display device comprising:
 a bank to expose a first light emitting portion, a second light emitting portion, and a third light emitting portion spaced apart from each other on a substrate;   a first light emitting element at the first light emitting portion to emit blue light;   a second light emitting element at the second light emitting portion to emit green light; and   a third light emitting element at the third light emitting portion to emit red light,   wherein a lower surface of a charge generation layer commonly provided in the first light emitting portion, the second light emitting portion, and the third light emitting portion is in contact with an electron transport layer at the first light emitting portion, in contact with a first optical compensation layer at the second light emitting portion, and in contact with a second optical compensation layer at the third light emitting portion.   
     
     
         14 . The light emitting display device according to  claim 13 , wherein the second optical compensation layer is thicker than the first optical compensation layer. 
     
     
         15 . The light emitting display device according to  claim 13 , wherein each of the first optical compensation layer and the second optical compensation layer is thicker than the charge generation layer. 
     
     
         16 . The light emitting display device according to  claim 13 , wherein:
 the first light emitting element includes a first blue light emitting layer below the electron transport layer and a second blue light emitting layer above the charge generation layer;   the second light emitting element includes a first green light emitting layer below the electron transport layer and a second green light emitting layer above the charge generation layer;   the third light emitting element includes a first red light emitting layer below the electron transport layer and a second red light emitting layer above the charge generation layer; and   a first vertical distance between the first blue light emitting layer and the charge generation layer is smaller than each of a second vertical distance between the first green light emitting layer and the charge generation layer and a third vertical distance between the first red light emitting layer and the charge generation layer.   
     
     
         17 . The light emitting display device according to  claim 16 , wherein:
 the first optical compensation layer and the second optical compensation layer have a first edge and a second edge, respectively, each on a bank around the first light emitting portion; and   an optical compensation layer non-formation area adjacent to the first edge and the second edge is provided on the bank, and the charge generation layer is in contact with the electron transport layer at the optical compensation layer non-formation area.   
     
     
         18 . The light emitting display device according to  claim 17 , wherein the charge generation layer is provided along surface steps of the first edge and the second edge. 
     
     
         19 . The light emitting display device according to  claim 13 , wherein the first optical compensation layer and the second optical compensation layer comprise an electron transport material. 
     
     
         20 . The light emitting display device according to  claim 13 , wherein:
 the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer; and   the N-type charge generation layer is in contact with the first optical compensation layer and the second optical compensation layer.